Because doctors spend less time on the job when their perceived risk of being sued for malpractice rises, those lost hours mean some 7 million people nationwide must find someone else to treat them.

That's the crux of a new study published this week by Brigham Young University economist Mark Showalter, who hastened to add that he and his research colleague, Eric Helland, are "not spouting any party line" regarding current proposals to cap malpractice awards nationwide.

The cost of malpractice insurance is one component of the ongoing national debate about health care reform, and the new study points out the non-monetary cost to patients, who have fewer available health care options when doctors cut back on their hours.

The researchers found that doctors reduce their workload by almost two hours per week when expected liability risk increases by 10 percent. That decline in hours nationwide equals one in every 35 physicians retiring without a replacement, Showalter said.

The study came out last week in the Journal of Law and Economics. Showalter and Helland, who previously served on the U.S. Council of Economic Advisers, used government survey data from the mid- and late 1980s to make the projections contained in the study.

Showalter said two surveys involving thousands of physicians — conducted five years apart — allowed them to estimate how expected malpractice risk has changed physician work patterns. Though some particulars within medicine have changed dramatically in the past 20 years, "the relative risk across medical specialties hasn't changed that much," he said.

"It was, and still is, the best data available," to determine how the constant threat of malpractice litigation affects work patterns.

The study found that doctors over 55 who own their own practices are far more sensitive to changes in liability risk than others, particularly because at that age, they begin to gradually cut their hours anyway, Showalter said.

The study has generated some interest by the American Medical Association and a few litigation attorneys since it became public, he said.